This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-207463, filed Jul. 16, 2002, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an improvement in auto-focus (AF) technique for a camera and, more particularly, to an improvement in so-called multi-point (multi) AF technique which has a plurality of distance measurement points within a frame.
2. Description of the Related Art
In general, if a camera has a plurality of distance measurement points in a frame as well as the one in the center of the frame, focus adjustment can be done regardless of the position of a main object to be photographed within the frame. On the other hand, the camera may be focused on an object which is not intended by the photographer.
In order to prevent the above erroneous focus adjustment, for example, U.S. Pat. No. 6,118,943 discloses a technique of selecting a distance measurement point with a manual switch. Recently, an increasing number of photographers enjoy photographing operation with finer focus position control. In more instances, photographers take photographs while performing focus adjustment in the manual mode, e.g., focusing the camera in consideration of the balance of a plurality of objects to be photographed or intentionally defocusing the camera instead of simple automatic focus adjustment for one point.
Many cameras having such an arrangement include special operation members for manual operation. By effectively using such operation members, a high value-added product can be provided which can reduce complexity in operation and suppress an increase in cost.
It is, therefore, an object of the present invention to provide a camera and a control method for a focusing device which can quickly cancel focus adjustment for an unintended object to be photographed, which tends to occur in multi AF operation, and perform focus control for an object intended by a photographer at high speed.
According to the first feature of the present invention, there is provided a camera having an auto-focus section having distance measurement points corresponding to a plurality of points in a frame,
the auto-focus section including a first determining section which determines a first candidate point of the plurality of points, and a second determining section which determines a second candidate point of the plurality of points which is different from the first candidate point,
the camera comprising:
a switch detecting section which detects operation of a predetermined switch by a photographer; and
a selecting section which selects/switches the first and second candidate points in accordance with a state detected by the switch detecting section.
According to the second feature of the present invention, there is provided a multi-point auto-focus camera having a selection/display control section which selects and displays at least one of a plurality of distance measurement points using a predetermined algorithm, comprising:
a switch which selects a manual focus mode; and
a point switching control section which switches the selected/displayed point in accordance with operation of the switch when control operation is performed by the selection/display control section.
According to the third feature of the present invention, there is provided a camera comprising:
an operating section which issues an instruction associated with focusing operation;
an auto-focus section which performs focusing operation on the basis of an in-focus point position in a frame;
a switching section which switches the in-focus point position in the frame; and
a control section which performs control to set an instruction from the operating section as a switching instruction to the switching section or a specific operation instruction associated with focusing operation other than the switching operation.
According to the fourth feature of the present invention, there is provided a control method for a focusing device which can switch in-focus point positions for auto-focus operation within a frame,
wherein an operation instruction by a specific operation section which issues an instruction associated with focusing operation is controlled as an instruction to switch the in-focus position within a predetermined period after the start of auto-focus operation, and as a specific instruction associated with another focusing operation other than the in-focus point position switching during a period other than the predetermined period.
Advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.